A global evaluation of streamflow drought characteristics
Open Access
- 21 July 2006
- journal article
- Published by Copernicus GmbH in Hydrology and Earth System Sciences
- Vol. 10 (4), 535-552
- https://doi.org/10.5194/hess-10-535-2006
Abstract
How drought is characterised depends on the purpose and region of the study and the available data. In case of regional applications or global comparison a standardisation of the methodology to characterise drought is preferable. In this study the threshold level method in combination with three common pooling procedures is applied to daily streamflow series from a wide range of hydrological regimes. Drought deficit characteristics, such as drought duration and deficit volume, are derived, and the methods are evaluated for their applicability for regional studies. Three different pooling procedures are evaluated: the moving-average procedure (MA-procedure), the inter-event time method (IT-method), and the sequent peak algorithm (SPA). The MA-procedure proved to be a flexible approach for the different series, and its parameter, the averaging interval, can easily be optimised for each stream. However, it modifies the discharge series and might introduce dependency between drought events. For the IT-method it is more difficult to find an optimal value for its parameter, the length of the excess period, in particular for flashy streams. The SPA can only be recommended as pooling procedure for the selection of annual maximum series of deficit characteristics and for very low threshold levels to ensure that events occurring shortly after major events are recognized. Furthermore, a frequency analysis of deficit volume and duration is conducted based on partial duration series of drought events. According to extreme value theory, excesses over a certain limit are Generalized Pareto (GP) distributed. It was found that this model indeed performed better than or equally to other distribution models. In general, the GP-model could be used for streams of all regime types. However, for intermittent streams, zero-flow periods should be treated as censored data. For catchments with frost during the winter season, summer and winter droughts have to be analysed separately.Keywords
This publication has 19 references indexed in Scilit:
- Drought IndicesPublished by Wiley ,2004
- Practical Extreme Value Modelling of Hydrological Floods and Droughts: A Case StudyExtremes, 2004
- Have streamflow droughts in Europe become more severe or frequent?International Journal of Climatology, 2001
- Three modelling approaches for seasonal streamflow droughts in southern Africa: the use of censored dataHydrological Sciences Journal, 2000
- On the definition and modelling of streamflow drought duration and deficit volumeHydrological Sciences Journal, 1997
- Regional frequency analysis of annual maximum streamflow droughtJournal of Hydrology, 1995
- Streamflow droughts of northern Nigerian riversHydrological Sciences Journal, 1994
- Indices of hydrological drought in IsraelJournal of Hydrology, 1987
- Generalized storage-reliability-yield relationshipsJournal of Hydrology, 1987
- Statistical Inference Using Extreme Order StatisticsThe Annals of Statistics, 1975